54 lines
1.6 KiB
Markdown
54 lines
1.6 KiB
Markdown
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^title Map Class
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^category core
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An associative collection that maps keys to values. More details [here](../maps.html).
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### **clear**
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Removes all entries
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### **count**
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The number of entries in the map.
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### **keys**
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A [Sequence](sequence.html) that can be used to iterate over the keys in the
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map. Note that iteration order is undefined. All keys will be iterated over,
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but may be in any order, and may even change between invocations of Wren.
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### **iterate**(iterator), **iteratorValue**(iterator)
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Implements the [iterator protocol](../control-flow.html#the-iterator-protocol)
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for iterating over the elements in the list.
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### **removeAt**(key)
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### **values**
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A [Sequence](sequence.html) that can be used to iterate over the values in the
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map. Note that iteration order is undefined. All values will be iterated over,
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but may be in any order, and may even change between invocations of Wren.
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If multiple keys are associated with the same value, the value will appear
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multiple times in the sequence.
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### **[**key**]** operator
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Gets the value associated with `key` in the map. If `key` is not present in the
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map, returns `null`.
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:::dart
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var map = {"george": "harrison", "ringo": "starr"}
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IO.print(map["ringo"]) // "starr".
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IO.print(map["pete"]) // "null".
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### **[**key**]=**(value) operator
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Associates `value` with `key` in the map. If `key` was already in the map, this
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replaces the previous association.
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It is a runtime error if the key is not a [Bool](bool.html),
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[Class](class.html), [Null](null.html), [Num](num.html), [Range](range.html),
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or [String](string.html).
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